Enhanced solvent deasphalting process for heavy hydrocarbon feedstocks utilizing solid adsorbent

Abstract

A solvent deasphalting of crude oil or petroleum heavy fractions and residues is carried out in the presence of a solid adsorbent, such as clay, silica, alumina and activated carbon, which adsorbs the contaminants and permits the solvent and oil fraction to be removed as a separate stream from which the solvent is recovered for recycling; the adsorbent with contaminants and the asphalt bottoms is mixed with aromatic and/or polar solvents to desorb the contaminants and washed as necessary, e.g., with benzene, toluene, xylenes and tetrahydrofuran, to clean adsorbant which is recovered and recycled; the solvent-asphalt mixture is sent to a fractionator for recovery and recycling of the aromatic or polar solvent. The bottoms from the fractionator include the concentrated PNA and contaminants and are further processes as appropriate.

1. A solvent deasphalting process comprising:
 a. introducing a hydrocarbon oil feedstock containing asphaltenes into a mixing vessel with a paraffinic solvent and a solid adsorbent material selected from the group consisting of attapulgus clay, alumina, silica activated carbon and zeolite catalyst materials; 
 b. mixing the solid asphaltenes formed in the paraffinic solvent phase with the adsorbent material for a time sufficient to adsorb sulfur- and nitrogen-containing polynuclear aromatic molecules on the adsorbent material; 
 c. separating the solid phase comprising asphaltenes and adsorbent from the oil/solvent mixture; 
 d. passing the oil/solvent mixture to a separation vessel to separate the deasphalted oil and paraffinic solvent and recovering the solvent for recycling to the mixing vessel; 
 e. passing the asphalt/adsorbent mixture to a filtration vessel with an aromatic or polar solvent to desorb the adsorbed compounds and to recover the solid asphalt phase; and 
 f. passing the aromatic or polar solvent mixture to a fractionator to recover the solvent. 
 
     
     
       2. The process of  claim 1  which is conducted at a temperature in the range of from 20° to 200° C. and at a pressure of from 1 to 100 kg/cm 2 . 
     
     
       3. The method of  claim 1  in which the solid phase is separated in step (c) by filtration to provide a cleaned feedstream substantially free of adsorbent. 
     
     
       4. The method of  claim 3  which includes desorbing and removing the nitrogen-containing PNA from the adsorbent material after the filtration step to thereby regenerate the adsorbent material. 
     
     
       5. The process of  claim 1 , wherein the hydrocarbon feedstock is derived a from natural source selected from crude oil, tar sands, bitumen and shale oils. 
     
     
       6. The process of  claim 1 , where the hydrocarbon feedstock is derived from refining processes selected from the group consisting of atmospheric and vacuum residue, fluid catalytic cracking, slurry oil, coker bottom oils, visbreaker bottoms and coal liquefaction oils. 
     
     
       7. The process of  claim 1 , wherein 1 to 50 V % of hydrocarbon feedstock is recovered as deasphalted oil for further refining processes including hydrocracking, fluid catalytic cracking and visbreaking. 
     
     
       8. The process of  claim 2  wherein 1 to 50 V % of hydrocarbon feedstock is recovered as asphalt for processing in an asphalt unit and refining processes including hydrocracking, coking and visbreaking. 
     
     
       9. The process of  claim 8 , wherein the high nitrogen content fraction is blended in fuel oil, or processed in an asphalt unit, a hydrocracking, coking or visbreaking unit. 
     
     
       10. The process of  claim 1 , wherein the adsorbent material is packed in a fixed bed column. 
     
     
       11. The process of  claim 2 , wherein the adsorbent packing is selected from adsorbent materials consisting of pellets, spheres, extrudates and natural products of a size in the range of 4-60 mesh.